RICHMOND, Va. — Broadening his attack on administration foreign policy, Mitt Romney accused Vice President Joe Biden on Friday of “doubling down on denial” in a dispute over security at a diplomatic post in Libya that was overrun by terrorists who killed the U.S. ambassador and three other Americans.

“The vice president directly contradicted the sworn testimony of State Department officials,” the Republican presidential candidate said, eager to stoke a controversy that has flared periodically since the attack on Sept. 11 “... American citizens have a right to know just what’s going on. And we’re going to find out.”

President Barack Obama had no campaign appearances during the day, leaving it to White House press secretary Jay Carney to defend Biden’s assertion in a campaign debate Thursday night that “we weren’t told” of an official request for more security at the site.

The spokesman rejected Romney’s claim of a contradiction. Biden “was speaking directly for himself and for the president. He meant the White House,” Carney said.

With his accusation, Romney once again pushed foreign policy to the forefront of a campaign dominated for more than a year by the economy, which has been painfully slow to recover from the worst recession in more than a half century.

The Republican challenger was campaigning across a pair of battleground states during the day, first in Virginia, which has 13 electoral votes, and then in Ohio, which has 18 electoral votes and where running mate Paul Ryan joined him.

Biden was in Wisconsin, Ryan’s home state, and one where polls give Obama a narrow lead despite a debate performance last week that was so poor it fueled a Republican comeback nationally and sent shudders through the ranks of Democratic partisans.

More than a week later, officials in both parties describe a race that has largely returned to the competitive situation in effect last summer, before the national political conventions and the emergence of a videotape in which Romney spoke dismissively of nearly half the country propelled the president to significant gains in the polls.

Now, many of the same surveys show a very tight race nationally and in most of the competitive states, although the president holds a small lead in public and private surveys in Ohio and Wisconsin.

Still struggling to blunt or reverse Romney’s rise in the polls, Obama’s campaign launched two new ads in several of the contested states. One shows the Republican being asked in a “60 Minutes” interview if it’s fair that he paid federal tax of about 14 percent last year on income of $20 million, while a $50,000 wage-earner paid a higher rate. “I think it’s the right way to encourage economic growth,” he says, and the narrator adds: “Lower tax rates for him than us. Is that the way to grow America?”

The second commercial appears aimed at recent comments Romney made suggesting he might not make opposition to abortion a priority. “Maybe you’re wondering what to believe about Mitt Romney,” it says, then shows him pledging to eliminate federal funding for Planned Parenthood.

With control of the Senate and all 435 House seats at stake along with the White House, outside groups that spent months stockpiling money were now in a race to spend it.

American Crossroads, a group backed by former White House strategist Karl Rove, announced this week it was spending $7.4 million in the presidential race, while an allied organization, Crossroads GPS, put down $4 million to help Republicans in five Senate races and another $8.1 million for 11 House campaigns — a total of nearly $20 million.

Some candidates seemed to be showing signs of campaign fatigue.

In a California House race between two Democrats, Rep. Brad Sherman seized the shoulder of Rep. Howard Berman during a debate, yanked him toward his chest and shouted, “You want to get into this?” The two men stood nose to nose before a sheriff’s deputy moved between them.

“I should not have done that,” conceded Sherman, 57, on Friday.

Said his 71-year-old rival: “It was like in the eighth grade, ‘You want to go over to the park on the corner and fight this out?’”

The two Democrats are pitted against each other because California advances the top two vote-getters in a primary to the general election, regardless of their party.

In the presidential race, Romney began the campaign week with a speech that criticized the Obama administration for showing a lack of leadership around the globe, particularly in the Middle East.

And he chose to end it with a direct challenge to Biden’s candor about the attack on the consulate in Benghazi, Libya.

“When the vice president of the United States directly contradicts the testimony, sworn testimony of State Department officials, American citizens have a right to know just what’s going on,” he said, referring to a hearing earlier in the week in a Republican-controlled House committee.

One official testified before the panel that he had been criticized for seeking additional security at the facility. A second said she personally had turned down requests for more protection at the facility in Benghazi.

Carney said, that despite Romney’s allegation, there was no contradiction between what Biden said and what the congressional committee had been told.

“Requests for individual personnel at the thousands of facilities ... are not adjudicated at the White House,” the spokesman said. “They are decided at the State Department.”

Biden, campaigning in LaCrosse, Wis., did not mention Libya on the day after the debate. Instead, he mocked Ryan for having said on Thursday night that a House budget proposal that he authored would not lead to drastic spending cuts in Medicare, education and other areas.

“Congressman Ryan saying his budget does not have spending cuts is like Gov. Romney standing in an unemployment line and saying, ‘I didn’t outsource you job, I offshored it,” he said, referring to a distinction Republicans sought to draw earlier in the campaign.

The controversy over Libya flared as both Romney and Obama looked ahead to their second debate, set for next Tuesday in Hempstead, N.Y.

After being accused by some Democrats of failing to prepare adequately for last week’s encounter, Obama arranged for several days of rehearsals in Williamsburg, Va.

Romney was flying home to Massachusetts on Saturday so he, too, could get ready for an event likely to be watched by a television audience measured in the tens of millions.

The two men will hold their third and final debate on Oct. 22 in Boca Raton, Fla.